Gun breech closing means



Feb. 4, 1958 P. w.-BuRK 2,821,885

GUN BREECI-I CLOSING MEANS Filed Aug. 2. 1951 4 Sheets-Sheet l INVENTOR PAUL W. BURK QEMW ATTORNEYS Feb. 4, 1958 P. w. BURK 2,821,885

GUN 'BREECH CLOSING MEANS.

Filed Aug. 2. 1951 4 Sheets-Sheet 2 N INVENTOR k. PAUL n. BUR/f Q/ZMW ATTORNEYS Feb. 4, 1958 P. w. BURYK 2,82 5

GUN BREECH CLOSING MEANS NNNNNN OR PAUL W. BURK ATTORNEYS Feb. 4, 1958 P. w. BL'JRK GUN BREECH CLOSING MEANS 4 Sheets-Sheet 4 Filed Aug. 2, 1951 INVENTOR8 PAUL W BURK LQA Unite GUN BREECH CLOSHIG MEANS Paul W. Eur-k, Washington, D. (1., assignor to the United States of America as represented by the Secretary of the Navy This invention relates to gun breech closing mechanisms and more particularly to a novel mechanism which, in conjunction with a round of ammunition being rammed into a gun breech, transfers the ramming energy from said round to a breech block, thereby closing said breech block behind the round and decelerating the latter from a relativelyhigh velocity to a relatively low velocity upon contact thereof with the breech.

Conventional breech blocks of guns employing fixed or semifixed ammunition usually comprise a heavy metallic member slidable vertically in a suitable housing to open or close the gun breech. The block is moved downwardly to the open position upon recoil of the gun through a cam operated crank or the like and is there held by spring pressed latches or other suitable hold-down means. Heretofore, the block has been moved to the closed position, upon tripping of the hold-down means, by a heavy spring. Cartridge case extractors have been positioned on each side of the block and provided with toes for engagement with the cartridge case flange. When the breech is opened, cam grooves in the side of the block engage suitable lugs on the extractor to move them rearwardly to flip the spent cartridge cases out of the breech, the extractors being retained in their rearward position as long as the block is open. When a new round i's-rammed into the gun, flanges'at the rear of the cartridge case strike the extractors with great force causing them to rock in the breech block cam groove, and though this action is occasionally utilized to trip the block hold-down means to enable the closing spring to operate, the extractors serve no other useful function during ramming and only cause excessive Wear on the moving parts of the breech mechanism and generally impede the loading of rounds and the operation of the gun. Furthermore, since the spring closed breech block moves independently of the speed of incoming rounds and thus closes the breech at a predetermined rate depending upon the strength of the spring, the maximum rate of fire can never exceed the limitations placed thereon by the speed with which the breech block closes.

The present invention converts What heretofore have til) at the lower end of the extractors so that as the cartridge flange engaging toes at the upper end of the extractors are engaged and moved toward the breech by an incoming round, the lugs engaging the block are moved upwardly and to the rear to impart a closing thrust to a suitable cam surface on the block. By closely relating breech mass to the velocity and mass of an incominground, the kinetic energy of the latter may be substantially trans ferred to the block through the extractor arms so that the round is decelerated to relatively low velocity by the ing the breech block partially closed by the rammed round time its flange contacts the breech face. The kinetic energy so transferred is not only used to raise the block but, by the proper relationship of mass and velocity, the present invention permits the block to be moved to closed position in a fraction of the time required for spring closing means, thus enabling relatively large caliber fully automatic guns to maintain a much higher rate of fire than that heretofore obtainable from prior guns of comparable caliber.

Hence one object of the present invention is to provide a mechanism for utilizing the kinetic energy of a rammed round of ammunition to close a gun breech block.

Another object of the present invention is to provide a breech closing mechanism which decelerates a rammed round of ammunition by absorbing the energy thereof in the acceleration of a gun breech block.

Still another object of the present invention is to provide a gunbreech closing mechanism which both decelerates a rammed round of ammunition and simultaneously closes the breech block of said gun.

Yet another object of the present invention is to provide in a gun, means for correlating the speed of breech block closing with the speed with which ammunition is rammed into the gun.

Still another object of the present invention is to provide a mechanism for closing a gun breech which permits a greater rate of fire to be obtained than heretofore has been possible.

Still another object of the present invention is to provide novel cartridge case extractors which serve to close the breech block and to decelerate an incoming round of ammunition.

Another object is the provision of a round loading and cartridge case ejecting means which can operate in any position or attitude independently of the forces of gravity.

Other objects and their attendant advantages will become apparent as the following detailed dscription is read in conjunction with the accompanying drawings wherein:

Fig. l is a partially schematic perspective view of the breech end of a gun, partly broken away, showing one embodiment of the breech closing mechanism of the present invention;

Fig. 2 is a perspective view of one form of cartridge case extractor which may be employed with the embodiment of Fig. 1;

Fig. 3 is a slightly reduced partially schematic side elevation of the embodiment of the invention illustrated in Fig. 1 showing a round being rammed into a gun;

Fig. 4 is a view similar to Fig. 3 but in changed position showing the breech block partly closed by a rammed round of ammunition;

Fig. 5 is a view similar to Figs. 3 and 4 but in changed position showing the breech block completely closed by a rammed round;

Fig. 6 is a reduced vertical cross-sectional view of the embodiment of Fig. 1 taken along a line substantially conforming to line 66 of Fig. 3;

Fig. 7 is a partially schematic partially exploded frontperspective view of a breech block incorporating a second embodiment of the present invention with portions thereof broken away;

Fig. 8 is a schematic reduced side elevation of the embodiment illustrated in Fig. 7 showing a cartridge being rammed into the breech of a gun;

Fig. 9 is a changed position view similar to Fig. 8 showof ammunition; and

Fig. 10 is a changed position view similar to Figs. 8 andv 9, showing the breech-block in its closed position.

With reference to the first embodiment of the present invention as illustratedin Figs, 1 to 6 inclusive the nu:

' 3 meral designates a gun barrel secured in the usual manner within a breech housing 21 which is slidable during a gun recoil cycle on the rails 23 of a conventional relatively stationary slide 22.

At the rear of the housing 21 behind the breech is the closing mechanism therefor comprisinga vertically moveable breech block 29 having vertical rails 27a on .op- .posite sides thereof which rails cooperate with vertical grooves 27 in bearing plates 26 secured in the sides of the housing. The breech block 29 is moveable up and .down to close or open the breech of the gun, and in Fig. 1, the block is shown traveling up in the direction of the arrow 45 approaching breech closed position behind a shell 34 already rammed into the gun. The rear of the housing 21 may be provided with an elongated U-shaped :notch and the top of the breech block may be-concave, as at 25a so that when it is in the down or breech-open position a curved surface is provided with the housing notch 25 to aid in directing the round as it is rammed into the gun breech. Any manual or recoil operated means (not shown), well known in the art, may be provided for moving block 29 to breech-open position and also any suitable latch or locking means may be employed for retaining the block in either its open or closed position, neither of said means being considered part of the present invention.

Extractors 31 are located in the breech housing at each side of the breech block and these members not only extract spent cartridges from the breech but also serve during loading of a new round as a novel means for both buffing the round and moving the breech block to closed position behind the round. The right and left hand extractors are identical but opposed and comprise fiat substantially sector shaped plates which operate between the sides of the breech block 29 and the bearing plates 26 (Fig. 6). The extractors are provided with cartridge case flange engaging toes 40 at their upper ends and near theirlower ends have opposed inner and outer bosses 32 and 35 which respectively operate in cam grooves 36 on the sides of the breech block and in stationary slots in the bearing plates 26. The forward edges 33 of the extractors are arcs of circles that have almost a pure rolling contact with the breech face 22 which is accompanied by some sliding motion. It is desirable that the extractor toes 40 have a substantially straight .line motion and therefore the profile of the stationary slot 30 conforms to the paths described by the outer bosses as the extractors roll on the breech face. This path may be readily determined by considering the center of outer boss 35 as a point inside the circumference of a rolling circle of which the arcnate edge 33 is a part. Since such a point described a prolatetrochoid it follows that as the extractorsroll on the breech 'face, the centers of bosses 35 describe .a segmento'f a-prolate trochoid, indicated by the broken line 310' in Fig. 3, which thus determines the profile of the s ot 30.

Theshape of'the 'breech'block cam groove 36 .is. determined as a resultant of slot 30 and the desired extractor motion with respect to breech block motion, for it is groove 36 that accurately locates the extractors with respect to breech block position during ejection and also serves to locate the extractor and the block upon receiving a closing thrust when the flange of a round impacts the toes at the upper ends of the extractors. For example, upon firing a round of ammunition, the extractors must remain in their forward or battery position until the forward face of the breech block has passed below the shell flange whereupon the extractor toes must be brought quickly to the rearto fiip the shell out of the breech. This action is accomplished through the curvedrupper portion 37 of the breech block cam groove. When the breech block is :inthe full open positiorathe extractor toes must be retained in their rear position to intercept the flange of a new cartridge case being rammed into the breech.'- Whenthisoccurg-as shown"inFig.3,the curved forward edges 33 of he ext a t rs r l on th breech fa 22 moving outer bosses 35 rearwardly and upwardly in stationary slot 30 substantially along the dotted trochoidal line 30'. The force transmitted through the inner lugs 32 to the upper portion of cam grooves 36 is perpendicular to the point of tangency of said lugs with said grooves and, for purposes of illustration, may be represented by the resultant vector line 47, which is readily resolved into horizontal and vertical components 48 and 49 respectively. In the early portion of the extractor travel, because of the shape of fixed slot 30, the vertical vector 49 very nearly coincides with the resultant vector 47 so that the breech block is given a large initial vertical acceleration. Thereafter, as observed in Fig. 4, a constantly decreasing upward vertical force is exerted upon the breech block until the inner bosses 35 of the extractors enter the lower straight portion of the grooves 36 at which point the major portion of the kinetic energy of the round has been transmitted to the breech block and the round thereby is decelerated from a high to a substantially low velocity at the time of contact of the flange thereof with the breech face. The breech block thereupon coasts" the remaining distance to the fully closed position of Fig. 6, decelerating enroute to arrive at the upper limit of its travel at a relatively low velocity where it may be retained by any suitable conventional breech locking means. If desired, the breech block guide grooves 27 may be slightly inclined forward from bottom to top, as illustrated in Figs. 4-6, so that as the breech block rises, it moves forward slightly and wedges the cartridge. case home.

Due to the fact that the available forces for moving the breech block are many times that caused by gravity, the closing time of the block is not appreciably affected by its operating position. It will be apparent that the speed of breech closing varies with the speed and weight of the incoming round and that therefore the weights of the operating elements, the shapes of the cam slots, and the speed of desired operation must be closely correlated to achieve the above result. However, with a fully automatic loading system the energy of incoming rounds can be accurately predicted and hence it is a relatively simple matter for one skilled in the art to construct the extractors and breech block with such proportions as to achieve the desired result. For example, it has been found that a round of ammunition weighing 33 pounds, traveling into the breech at an initial velocity of 15 feet per second, and striking extractors whose .arcs 33 have a radius of 4.5 inches imparts suflicient kinetic energy to a 75 pound breech block to move it a distance of 6.5 inches, from full breech open to full breech closed positions, in approximately 0.07 second which is a fraction of the breech closing time for prior guns of comparable caliber employing spring operated closing means.

Referring now to the secondembodimcnt of the present invention illustrated in Figs. 7 to l0 inclusive, the nutneral 60 refers tothe rear portion of a gun housing corresponding to the housing21 of Fig. -1. A breech block 62, having guide portions 64 on the sides thereof which cooperate with grooves 63 in suitable bearing blocks 61 secured to the sides of 'thehousing, moves vertically in the housing'to wopenor close the breech of the gun.

Similar butoppositely formed extractors 68 are located on opposite sides of the breech block, each being provided at its upper end with an inwardly projecting toe 69 which is engageable by the flange 84 of a cartridge case 83 as the caseis rammed into the breech. Outwardly projecting 1130586570 on the loweriends .of the extractor arepivoted withincam blocks 71 which .operate in forwa dly otting own a d y endi g grooves in the s esl e housingv Qppos d t th ute osse 7 e s t nredflnwardly projec i g bosse h c co perat with cam grooves 67 cut into the. ,lower. forward portion t eb eeqh. block 62,. :Qn the tun r .side o th rapies: portion of each extractor is a narrow elongated boss 74 and spaced thereabove is a cylindrical boss 75. These bosses cooperate with cam surfaces 76' and grooves 76 on the sides of the breech block which cam to, and accurately locate in, battery position the extractor toes 69 when the block is moved to closed position by means other than a rammed round of ammunition. As in the first embodiment, the forward edges 80 of the extractors are arcuate to enable them to rock on the breech face as they move between battery and ejecting positions. An outwardly extending bracket 81 is provided on the outer surface of each extractor against which bears a spring urged plunger 78, recessed in the sides of the housing, for the purpose of locating the extractors in the correct rearward position.

Figs. 8 through 10 are a series of operational views showing the manner in which the breech block is moved to closed position by a rammed round of ammunition. With the block 62 in the down or breech open position of Fig. 8, the extractor toes 69 are properly located in their rear position through the action of the upper portion of cam surface 67 on the inner boss 73 and through the spring urged plunger 78. Each cam block 71, carrying outer boss 70, is disposed at the forward lower end of the stationary guide slot 72 in the side of the breech housing. The forward lower edges 80' of the extractors are flat to abut the breech face 66 and insure further accurate location of the extractor toes. When a cartridge 83 is rammed into the breech, flange 84 thereof contacts the toes 69 moving them in the direction of the arrow 85. Thereupon, as shown in Fig. 9, surfaces 80 of the extractors roll on the breech face 66 urging the lower end of the extractors rearwardly thereby causing cam block 71 to slide diagonally upward to impart, through inner boss 73, a substantially vertical thrust component to the cam surface 67 of the breech block. Throughout extractor travel, boss 73 imparts a decreasing upward thrust to the breech block until the flange 84 of the cartridge case abuts the breech face 66. At this stage of operation the small extractor guide bosses 74 and 75 are in alignment with the grooves 76 on the sides of the breech block which, through its residual momentum, continues to travel upwardly. The grooves 76 in the sides of the breech block, meanwhile, serve to retain the extractor toes in their forward position and when the breech block reaches the limit of its upward travel, which is the position shown in dotted lines in Fig. 10, it may be retained in any conventional manner.

After the cartridge has been fired conventional recoil operated means (not shown) move the breech block downwardly to breech open position. Bosses 74 and 75 remain in their grooves 76 until the breech block has passed below the shell at which time cams 67 engage inner bosses 73 causing the extractors through curved surfaces 80 to roll on the breech face 66 and the extractor toes 69 to move rearwardly to remove the spent case from the breech. As the block approaches the end of its downward travel the extractor toes 69 are rapidly accelerated to flip the cartridge case clear of the gun breech. The breech block may thereupon be buffed to a stop in the usual manner and plungers 78 thereafter relocate the extractors in the ramming position of Fig. 8 in readiness to receive a new cartridge case.

As in the embodiment of Fig. 1 it will be apparent that the speed of breech block closing is dependent upon the mass and velocity of the incoming round and the mass and distance of travel of the breech block. Since these factors may be readily controlled or determined by one skilled in the art. a variety of forms or modifications may be permitted without departing from the scope of the present invention.

The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

What is claimed is:

1. A device for closing a gun breech comprising; a breech housing providing a transverse rear breech face, a breech block movable in said housing between breech open and breech closed positions, sector shaped cartridge case extractor plates on opposite sides of said breech housing each having an arcuate edge in rolling contact with the face of said breech housing, toes on one end of the arcuate edge of each extractor plate for engagement with the flange of a cartridge case, opposed inner and outer lugs on the opposite end of each, extractor plate inwardly of the arcuate edge and movable in opposition to said toes as said extractors roll on said breech face, said breech housing having a trochoidal guide slot for each outer lug conforming to the paths of said respective outer lugs as the extractor plates roll on said breech face, said breech block being provided with cam surfaces slidably engaged by said inner lugs and shaped to throw said breech block into closed position responsive to movement of said lugs in one direction along said trochoidal paths, said lugs being moved along said trochoidal paths upon said toes being moved toward said breech by a rammed cartridge case, said inner lug acting on said breech block cam means thereby to move said block to breech closed position behind said cartridge case with a large initial acceleration in the early portion of the extractor travel toward said breech.

2. A device for utilizing the energy of a rammed round of ammunition for closing a gun breech comprising; a breech housing at the rear of said gun breech, a breech block movable in said housing from breech open to breech closed position, sector shaped cartridge case extractor plates positioned in said housing between the sides thereof and the sides of said breech block and having arcuate forward edges in rolling contact with the face of said gun breech, inwardly projecting toes on one arcuate end of each of said sector plates engageable by the flange of a cartridge case, and opposed inner and outer bosses on the opposite sides of the other arcuate end of said sector plates, said breech housing having forwardly sloping trochoidal slots to receive said outer bosses and conforming to paths of said outer bosses as the extractor plates roll on said breech face and said breech block having forwardly curving cam grooves to receive said inner bosses, said trochoidal slots and said forwardly curving grooves being shaped for cooperation with said extractor bosses to translate the kinetic energy of said rammed round into closing energy of said breech block upon movement of said extractors by impact of said round against said toes with a large initial acceleration during the early portion of said extractor movement.

3. Gun breech closing means comprising a breech housing providing a transverse rear breech face and having forwardly sloping trochoidal slots in the sides thereof, a breech block movable in said housing from breech open to breech closed position and having arcuate cam grooves in the sides thereof, sector shaped extractors movable between battery and ramming position interposed between the sides of said housing and said block and having arcuate forward edges, inner and outer lugs on said extractors respectively operating in said cam grooves and said trochoidal slots for positioning the arcuate edges of said extractors in rolling contact with said breech face in accordance with the position of said block, the curvature of said trochoidal slots conforming to the path of travel of said outer lugs upon rolling of said extractors on said breech face, said extractors being in ramming position with said block in breech open position and in battery position with said block in breech closed position, and toes on said extractors for receiving the impact of a rammed round of ammunition to move said extractors from ramming toward battery position, the inner lugs on said extractors coacting with said cam grooves to transfer the kinetic energy of said round to said breech block to move, i to b ch ose positionq t th ailargejinitial acbqleration n he ear part9? ,r aiifbl ieesh dosin movement.

4, Means for closing a gun breech comprising abreech l ousingproviding a transverse rear breech face, a breech block vertically slidable in said housing behind said breech face to open and close the same, extractors between said breech block and said housing, movable between ramming and battery position, an arcuate surface on said extractors rollable on said "breech face during movement of said extractors, transversely opposed inner and outer lugs on one end of said extractors, upwardly extending forwardly curved cam surfaces on said breech block cooperating with said inner lugs, forwardly sloping downwardly extending trochoidally curved guides in the sides of said breech housing cooperating with said outer lugs, cartridge flange engaging toes on the, other end of said extractors, said guide and said .cam surfaces 'serving to locate said toes in ramming position with said block in breech open position, said g n-ides beingso curved that said extractors upon impactthereof by a rammed cartridge case are constrained to rolling movement on said breech face by said outer lugs in followingsaid tro'choidal curve, said guides directing said lugs rearward iyand 11pwardly to impart through said cam surfaces the-energy of said cartridge to said block to move the same to breech closed position with a large initial acceleration'in the early portion of extractor rolling movementtoward said breech. I

5. Gun breech closing means comprising a breech housing having parallel slots in thejsidesthereof, a breech block longitudinally movablein said housing from breech open to breech closed position and having gro'oves in its sides, said grooves including arcuate cam groove portions commencing at the front of the breech block and continuously extending rearwardly of and laterally from said gun breech, and longitudinal rectilinear cam groove portions extending from said arcuate cam groove portions and laterally of .the gun breech, sector shaped extractors movable between battery and ramming position interposed between the sides of said housing and said block and having arcuate forward edges, inner and outer lugs on said extractors respectively operating in said cam grooves and said slots, said slots being shaped to define forwardly and downwardly sloping oblate trochoidal camming paths for said outer lugs for positioning the arcuate edges of said extractors in rolling contact with said breech face in accordance with the position of said block, said extractors being in ramming position with said block in breech open position and in battery position with said block in breech closed position, and toes on said extractors for receiving the impact of a rammed round of ammunition to move said extractors from ramming toward battery position with said outer lugs traveling upwardly and rearwardly along said oblate trochoidal cam paths and said inner lugs similarly traveling upwardly and rearwardly and thereby coacting with said cam grooves to transfer the kinetic energy of said round to said breech block to move it to breech closed position.

References Cited in the file of this patent UNITED STATES PATENTS 625,326 Driggs May 23, 1899 1,707,444 McCann r Apr. 2, 1929 2,434,972 Vick Jan. 27, 1948 2,462,920 Summerbell Mar. 1, 1949 

